Fun fact about Thavarian Onions (not fun)

[HEC-]

getting 1 rank takes 1 week

Actually - even without the weekly Challenge bonus which equals to 15% (5 + 10) of total XP needed per each level you can do one full level in 50 hours - e.g. 2 days and 2 hours you you'd feed it exactly every hour twice - this is pre lvl 10 where with Cleansparkly stables each training gives 1% of XP needed so 100 Krakka roots will take it to level up. From level 10 it's only 0.9% so 111 Krakka Roots + tiny bit to complete once you take the choco out. I've managed last weekend to level 2 chocos fully one level before the clean status expired.